I've seen the satnav not start up sometimes, just tend to live with it as it's so infrequent

Good choice, I've got the same

Depends on your luck, it should be ok, what other faults do you have?

Have a look here, it's been mentioned a few times (like here viewtopic.php?f=31&t=7554 ), the cause is the exhaust pressure sensor, the pipe gets blocked and you get this random fault. You'll also have code C1130 stored in the ecu

If it is due to the lights, then you can check by the sun/moon button on the controls.

The nissan parking sensors come with all the templates needed for marking out the holes, jsut need a hole cutter.

Aren't new tyres 8mm?

Cant help much, though I am planning to do the rear parking sensors on myself.

Diesels are normally slightly cheaper to service, no spark plugs, the rest is pretty much the same.

Any photos of what style they are??

Pitu you are so far away, I'd have taken them